An electrophotographic copying apparatus having edited image forming and data input capabilities is known which includes an external edited data input unit (hereinafter referred to as editor module) also having such capabilities. A copying apparatus of this type is per se equipped with means enabling the operator to select the edited copy mode of operation and entering data with which the edited copy mode of operation is to be carried out in the apparatus. Such edited copy mode select and data input means include a set of manually operated control keys arranged on, for example, the control panel of the apparatus. Such control keys include a key for selecting an edited copy mode of operation, and keys for specifying a desired limited area or, particularly, the coordinates defining such an area, of a document sheet within which images are to be reproduced in the edited copy mode.
The eraser unit is provided in addition to such eraser unit select and data input means and has manually operated control keys to be used to achieve functions essentially similar to the edited image forming and data input capabilities of the apparatus per se. The eraser unit further has a panel surface (hereinafter referred to as tablet) on which a document sheet to be duplicated in an eraser unit may be placed. By manually applying a localized pressure to desired points of such a tablet, the operator can designate any desired graphical pattern or area (hereinafter referred to as edited copy area) defined by the coordinate points respectively specified by the depressed points of the tablet. Thus, the copying apparatus may perform an eraser unit operation either at a request from the control panel of the apparatus per se or at a request from the external eraser unit.